This invention relates generally to a developing device useful in diazotype reproduction apparatus, and more particularly, to the automatic control and operation of metering elements for controlling the amount of liquid developing agent that is applied to the light-sensitive diazotype papers.
The developing devices that are employed in reproducing apparatus which use diazotype sensitized sheets and rely on the application thereto of metered quantities of a liquid developing agent are well known. The devices generally comprise a motor-driven applicator roller having a special surface capable of carrying a metered quantity of developing liquid on the surface thereof and a wiper blade for removing the excess liquid. In addition to such a wiper blade, there is provided a pressure blade which is positioned against the surface of the roller which serves to press the light-sensitive diazotype paper against the surface to transfer the metered amount of liquid thereon.
Both the wiper blade and the pressure blade are assembled in a position adjacent to the applicator roller in such a manner so as to be moved into an operative position and out of an operative position in a certain prescribed manner, automatically; and further, to make adjustments in the wiper blade so as to increase or decrease its metering effect.
A known device of this kind is in use in diazotype developing machines which employ a cam control with cam followers for automatically controlling and operating the movement of the pressure blade and wiper blade in relation to the applicator roller. Such cam control devices are fully satisfactory; however, they are not without certain deficiencies. Such deficiencies reside in the complexity of the construction and because of its complexity, the high cost of fabricating such a mechanism. For example, such a cam mechanism requires a driving system comprising two separate motors and a special electrical circuit for each of such motors. Moreover, the mechanism requires considerable space within the reproducing apparatus thereby increasing the overall size of the equipment.